Method of making a strip of rubber material



Dec. 3, 1935 H. M. DODGE METHOD OF MAKING A STRIP OF RUBBER MATERIAL Filed June 8, 1954 Patented Dec. 3, 1935 PATENT OFFICE mrrnon or mama A straw or nnnara m'mamr.

Howard M. Dodge, Akron, Ohio, assignor to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application June 8, 1934, Serial No. 729,661

3 Claims. (CI. 18-59) This invention relates to rubber strip material comprising sponge rubber and to the method of making such material.

The principal objects of the invention are to 5 provide an article having a cushioning body of sponge rubber and a tough, thin impervious and elastic cover of soft solid rubber. Other objects will appear from the following description and the accompanying drawing.

10 In the drawing:

Fig. 1 is a side view of an extruding machine, illustrating one step in the production of a strip article.

Fig. 2 is a perspective view illustrating another 15 step in the method.

Fig. 3 is a perspective view of a mold with the strips therein.

Fig. 4 is a view of a coagulant dip tank with an article suspended therein.

20 Fig. 5 is a view of a tank for applying a rubber coating to an article.

Fig. 6 is a perspective view of a length of rubber tubing, being one of the articles made according to the invention.

25 Referring to the drawing, it is often desired to produce a strip of rubber material having extremely soft and deformable walls but impervious to moisture and having relatively high tensile strength or resistance to stretching. For example 30 drainage tubing, for use in surgical operations must have impervious surfaces and be relatively stiff, yet it is desirable that the walls of the tubing be soft so as not to irritate delicate tissues. Such a tube may be made according to this in- 35 vention as shown in Fig. 6, wherein the inner surface I and outer surface I l are formed of flexible impervious rubber and an intermediate layer 12 of soft sponge or cellular rubber is provided.

It is also desirable to provide glass-run channel,

40 header strips, and similar strip materials, used in the manufacture of automobiles and refrigerators, where such strip materials are used as seal- .ing strips, with great resistance to stretch, imperviousness to moisture, and low resistance to lateral 45 distortion and compression.

In either case my invention contemplates the provision of a rubber core member which may to be used as a channel, is shown at l9 and passes from the machine to a travelling apron 20 supported by a pulley 2|.

Where the core element I0 is of tubular form it may then be blown onto a mandrel 22 for 'convenience in handling, asshown in Fig. 2. A previously prepared strip of unvulcanized sponge rubber composition 23 is now applied over the surface of the core, whether the core is supported upon a mandrel or not, the core first being cleaned of dust as by sponging it with a rubber solvent.

The core covered with sponge rubber composition is then placed in a mold 24 as illustrated in Fig. 3. The mold cavities 25 are larger than the covered core to provide space for expansion of the sponge rubber composition. Heat is applied to vulcanize the core and to cause the sponge rubber composition to expand and fill the mold cavity where it becomes vulcanized.

After vulcanization, which may be complete or only partial, the facing II of impervious rubber is applied. This is preferably accomplished by applying a coating of a rubber coagulant and then 7 depositing thereon rubber from an aqueous dispersion thereof. For this purpose the strip may be first immersed in a tank 26 containing a coagulant solution 21. The strip preferably is then completely 'or partially dried and is then imm'ersed in a tank 28 containing an aqueous dis- 30 persion of rubber 29, either natural latex or an artificial dispersion.

After the impervious coating H has been applied the strip is subjected to further vulcanization at a. low-temperature and preferably while unconfined. This may be accomplished in a heated oven. By vulcanizing at a relatively low temperature, further blowing of the sponge rubber compound is avoided. v

When surgical drainage tubing, such as is illus- 40 trated in Fig. 6, is made by this method the tube comprising the core has sufficient support to prevent its collapsing in use. "The sponge rubber provides a soft cushion and the pliable impervious cover provides a smooth non-irritating surface to contact with the tissues.

I claim:

1. The method of making a strip of rubber material which comprises forming an unvulcanize'd rubber core, applying thereto a layer of sponge rubber composition, vulcanizing the strip while the strip is enclosed in a mold, applying an impervious cover of rubber over the outside of the strip, and vulcanizing the cover while the strip is unconfined.

2 I spasms 2. The method of making a strip of rubber material which comprises forming an unvulcanized rubber core, applying thereto a layer of sponge rubber composition, vulcanizing the strip while the strip is enclosed in a mold, depositing a layer at rubber over the assembled strip from an aqueous dispersion of rubber to provide an impervious cover, and vulcanizing the cover.

3. The method of making a strip of rubber material which comprises forming an unvulcanized rubber core, applying thereto a layer of sponge rubber composition. vulcanizing the strip while the strip is enclosed in a mold, depositing a. layer of rubber over the assembled strip from an aqueous dispersion of rubber to provide an impervious cover, and vulcanizing the cover while the strip is unconfined.

' HOWARD M. DODGE. 

